Delta(1)-pyrroline-5-carboxylate dehydrogenase, PutA
The proline catabolic enzymes of the aldehyde dehydrogenase (ALDH) protein superfamily, proline dehydrogenase and Delta(1)-pyrroline-5-carboxylate dehydrogenase (P5CDH, (EC=1.5.1.12 )), catalyze the two-step oxidation of proline to glutamate; P5CDH catalyzes the oxidation of glutamate semialdehyde, utilizing NAD+ as the electron acceptor. In some bacteria, the two enzymes are fused into the bifunctional flavoenzyme, proline utilization A (PutA) These enzymes play important roles in cellular redox control, superoxide generation, and apoptosis. In certain prokaryotes such as Escherichia coli, PutA is also a transcriptional repressor of the proline utilization genes.